


Reference Material

by Anonymous



Category: Supernatural
Genre: Anal Fingering, Bottom Castiel, Bottom Castiel/Top Sam Winchester, Castiel and Sam Winchester Hug, Dirty Talk, Dom Sam Winchester, Kink Negotiation, M/M, Manhandling, Oil Gland Kink, Protective Sam Winchester, Sam scares Cas, Sassy Castiel, Sexual Experimentation, Wing Kink, Wing Oil
Language: English
Status: Completed
Published: 2018-11-18
Updated: 2018-11-18
Packaged: 2019-08-25 14:03:40
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,894
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16662325
Author URL: https://archiveofourown.org/
Summary: When Sam finds a book about the ways to sexually excite angels, he’s very keen to try it out with Cas.It’s not exactly a smooth path.Dean being a little shit doesn’t help.





	Reference Material

Sam finds the book by accident. 

The plumbing in the bunker has, mostly, stood the test of time. It's a little light on water pressure and, in winter, the radiators can take most of the day to heat up, but nobody's complaining. 

It's home, with all its imperfections. 

But one of those current imperfections is the pixie infestation in a corner of the basement archive. They've finally corralled the little pests and kicked them out, but not before they decorated most of the room with their floral odored piss. 

Everything in there is going to stink like a wilting rose garden unless the books are dried and aired, the furniture washed down. 

Dean disappears for that part. In hindsight, Sam's glad because it's there he makes his discovery. 

After two hours’ work, all he has to move is the bookcase in the far corner and as he pulls it away from the wall, he hears something fall down behind it. 

Wary, he reaches for it and huffs in amusement when he dusts off the cover. 

_The Biology of Angels_. 

He opens it, scans the first few pages, finds it reads more like a journal than an anatomical guide. 

Still, more knowledge isn't always a bad thing, and he has more than a passing interest in the subject. The book being hidden (no way it just fell down there) and the curious nature of its composition has his interest piqued anyway. 

He decides tonight, when Dean's turned in, he’ll see what new things he can learn about Cas….well, angels in general. 

++

He makes a steady progress through the book over the next two days, discovering a little about the man who wrote it (a former legacy, no surprise there), and some no longer useful information on the hierarchy of angels. 

There aren’t enough angels left to have a hierarchy. He leaves it alone for a while after that, trying not to think what Cas is going through now he knows his species is on the cusp of extinction. 

But he does think about how badly he wants Cas home. Sam can’t do anything to help with the situation in Heaven; but he can make sure Cas knows he always has a home wherever he, Sam, is. 

++

Dean has no good reason to be in his room, but that’s never stopped him. Whatever he was up to, Sam only knows about it because he hears Dean chuckle over dinner and looks up to find Dean with a forkful full of pasta in one hand and the book in the other. 

“Seriously?”

Dean gives him a smirk. “Seriously? You dog, Sam. Always the quiet ones.”

Sam doesn’t know what he’s going on about, but his suggestive tone and the _leer_ make his cheeks heat. 

“You’re the only person I know that could make a book on anatomy seem filthy.”

Dean sniggers. “Yeah. I’m not sure either of us is old enough to be reading this thing.”

Sam snatches it from Dean’s hand and gets up, meal forgotten. Why does Dean have to make everything so damn awkward?

“Stay out of my room, okay?”

He goes, and just knows Dean is mouthing ‘stay out of my room’ at his back with an asshole look on his face. 

Fucker. 

Later, though, like he needs to go back to the book just to prove his big brother is a giant child, Sam skips forward a few chapters to where he figures Dean was reading. 

His jaw drops. 

Yeah, he’s going to owe Dean an apology in the morning. 

++

Cas returns to them two days later. 

Sam’s been a very busy boyfriend in the meantime. He’s super nervous though, because he has no way of knowing if anything in the book is accurate or might turn out to be really offensive to angels. 

And because, after Dean gets his turn hugging Cas, he keeps grinning at them and making suggestive comments that Cas, thankfully, looks too tired to process. 

Of course Dean would do that. He knows Sam’s been holed up with the book. And he knows Sam’s been up to something the past couple of days if not quite what. 

Finally, though, when Cas has settled and told them there’s no real news on Michael, or on a way to restore power to Heaven, Sam can see how low he seems. 

He gets up and he holds out his hand to his angel and Cas takes it. Sam guides him to his feet and leads Cas to their room. 

He ushers Cas in first, and turns on the light just as he closes the door. 

Cas stands there, staring at the bed. 

Sam doesn’t dare to move. He’s so sure now that this is a terrible mistake. That the book was wrong or he’s misinterpreted it. 

Hell, maybe Dean wrote the damn thing himself and left it there, just waiting for Sam to fall in love with Cas and find it and…

He’s standing there, driving himself crazy. 

Cas turns around, finally, and Sam always almost loses himself when his angel looks at him like that, like Sam is his entire existence. 

He pulls Sam to him, and they collapse into the nest Sam’s made on the bed, an awkward tangle of bodies and clothing but Sam doesn’t mind. 

Later, Cas lying in Sam’s arms, looking up at the blanket Sam managed to pin so it fell over the bed like a canopy, the angel asks what prompted this?

Wonderful and needed and just the only nice surprise Cas feels like he’s had since Dean came home. 

Sam snuggles Cas closer and promises to tell him in the morning. 

++

Dean must have gone to bed late because it’s just them for breakfast. Cas sips his coffee and listens as Sam explains finding the book and passes it to him. 

He loves that curious look Cas gets on his face when presented with something new to study or learn or solve. 

He also loves the tinge that spreads over his skin as he moves past the, uh, more general chapters and onto the section that deals with angelic intercourse. 

Sam feels kind of dirty just thinking it, which is weird because neither of them are blushing virgins (not even with each other). But up until now, it’s been pretty much basic stuff because Cas is not real good at being able to say what he wants or needs. 

This book is a whole new play, and Sam is certain of two things right then. 

One, he is so very turned on watching Cas skim through that book. Maybe getting excited by the same parts that got Sam excited. 

Two, he really wants to take that angel back to bed and try every single idea it’s given him. Right now. 

Dean finally comes stumbling in, sleep addled, a minute later. He grabs coffee and joins them at the table and his eyes fall on the book. 

“Afternoon,” Sam says, before his brother can start his shit. He doesn’t really know where Cas is over this…. It’s something they need to talk about. 

Dean grins at them. “Didn’t want to come in here and find you bending Cas over the table.”

Sam’s speechless. Why though is he ever surprised that Dean can be crass and infantile?

But Cas, Cas nearly knocks Sam off his chair. 

“It’s alright,” he tells Dean, standing. “We wiped it down afterwards. Sam, I’ll be in the archive if you need me.”

Now it’s Dean who’s speechless. Mouth open, trying to work, nothing coming out. 

Until, finally… “Dude, gross.” He scoots back like the table might have cooties.

Sam’s appetite is suddenly not for breakfast. 

“Yeah,” he says, rising to go after Cas. “Watch in case we missed a bit.”

He flees, grinning madly at Dean cursing a blue streak after him.

++

“You need to tell me if I’m hurting you,” Sam says. 

Cas looks back over his shoulder, already looking like Sam’s fucked him hard and they haven’t really started. 

“I will, but you won’t. Just don’t squeeze too hard. Only a little pressure’s required.”

Sam nods and shifts back on the bed and watches as Cas’s wings shimmer into view. He strokes his finger down the length of Cas’s spine, grinning when the wings jerk and twitch. 

“Sam,” Cas complains. 

Slightly chastised, because he knows how ticklish Cas is, Sam presses a little kiss between the angel’s shoulder blades. “Sorry,”. 

In response, Cas flexes his wings, and Sam sees the oil glands. 

They’re nestled beneath a cushioning clump of feathers, a delicate swelling in each side that Sam’s never really thought about much before. 

Now, though, they have his attention. 

His first touches are hesitant; he knows from the book, from Cas, that the glands are sensitive. Much as he wants this to happen, doing something that will hurt Cas, cause him pain, is not acceptable. 

He gets a little bolder when neither of those things happens, and he starts to feel a thrumming moving through the wings. 

“You know,” he says. “When I read about this in the book. When I read about all the things I wanted to do to you. How I could make you feel? The ways I could pleasure you, Cas. Make you come.”

His fingers feel slick suddenly. Cas’s glands are leaking, which proves the book was right about that. 

It gives him another idea. “You know how fucking hot you are, Cas? So good for me, trusting me like this. I’m gonna make you feel so good, Cas. Gonna take care of you. Come on, Cas. Give it up for me.”

It’s awkward, but he reaches around to stroke Cas, the oil slicking him up. Cas’s breathing picks up, his entire body seems to be trembling. 

His glands are producing so much oil, it’s dribbling onto his hand, the sheets. Sam slicks his fingers up and slowly circles Cas’s hole, dipping his fingertip inside. 

He steadily works him open, sliding his fingers in and out, coating Cas’s channel with the liquid from his glands. 

There’s something thoroughly filthy about this and Sam’s hard from it, from the small pants from Cas, from how any minute he’ll be fucking Cas’s own wing oil deep inside him. 

He rubs the oil over his dick, feeling deliciously sinful in the act, and then carefully sinks into the angel. Sits for a moment and lets Cas adjust to him. 

And then he moves. He puts one hand on Cas’s shoulder, balancing himself, and the other on his hip. Cas pushes back to meet each thrust, tightening down, and they must both have been so fucking close because Cas screams his name once and then he’s coming hard. 

Sam rides him through it, until his own release sends him crashing down on top of Cas. Just as well he can take it. 

He can only let it happen when Cas shifts him so he can turn over and then Sam’s nestled in Cas’s embrace, his black wings wrapped around them. 

“Okay?” He asks. He’s pretty sure the answer is yes but he needs to hear it. 

Cas presses a kiss to his forehead. “Okay.”

++

They don’t have long. Dean’s only gone to pick up pizza and beer, but Sam’s sure that’ll be enough. 

He catches Cas as he’s clearing the books from their save-the-world study session and presses up against his back, pinning him against the stack. 

“Think I can get you to come before Dean gets back?”

Cas huffs at him. “I’m not sitting in damp underwear for the duration.”

Sam nuzzles behind his ear, making sure Cas can feel just how hungry he is for him right now. “We can shower after. I’ll get you cleaned up.”

He backs up enough to turn Cas around before pinning him again with his body. He kisses him, hot and dirty, and then grabs Cas’s wrists and guides them up to shoulder height. Holds them there. 

“Sam,” Cas warns. 

Sam kisses him quiet, and then squeezes his wrists meaningfully. “Stay right like that,” he orders. “Or I’ll tie you to this.”

He crowds in on him again, slipping his hand into Cas’s pants, working on that damp patch problem that he quite likes the idea of now that Cas has put it in his head. 

Cas wriggles against him, which Sam also kind of likes, but it is distracting. He captures Cas’s wrists in one hand and holds them above Cas’s head before giving him a stern look. 

“Don’t you move,” he warns. 

“Sam, stop.”

“Haven’t even gotten started.”

“Sam!”

And he realises then, Cas isn’t playing. He looks desperate and not in keeping with wanting Sam to make him come. 

He sounds scared. 

Sam drops his grip and steps straight back, giving Cas a safe zone. 

He watches Cas lower his arms, watches Cas pulling himself slowly together. All the time kicking himself for not noticing Cas was in distress and for not checking this type of play would be okay. 

“Cas,” he says, finally. “Cas, are you alright?”

Cas glances guiltily at him. “Yes. Sam, I’m sorry. But I can’t…”

“No, no. No.” Sam almost reaches for him, then abandons the idea at the last moment. “Cas, no. This one is on me. I’m the one who should be sorry. And we never do anything you’re not comfortable with.”

He can’t believe he took it for granted that just because angels apparently like being held down during sex, ordered not to move, that Cas would like it too. 

Cas is like no other angel in existence. 

He’s beyond relieved when Cas steps into his space and snuggles up against him, making an unhappy noise when Sam hesitates in hugging him back. 

“Just…” Cas says, “I…. It reminds me of…”

Sam kisses the tip of his head. Yeah, he can figure what it reminds Cas of.

Cas tilts his head back, an obvious invite for Sam to be kissing him elsewhere. Sam obliges, and they’re still at it when Dean disturbs them by dropping the case of beer on the table. 

“You two better not be making out back there,” he calls to them. 

Sam checks again on Cas, but he seems more settled now. More at ease with Sam touching him. 

He leads Cas back to where Dean’s laying out pizza on three plates. 

“Dimmer switch your Grace,” he tells Cas. “We’ve earned a night off.”

Sam watches Cas eat pizza and drink beer and thinks seriously about burning that damn book. 

++

When he decides to do just that the next morning, he finds the book’s gone. His first thought is _dammit, Dean_. He’s not in the mood for any smartass comments, especially not after last night. 

So when he finds Dean tinkering under the Impala’s hood, and says his name sharply, he gets a bitter pleasure hearing the thud as his brother’s head collides with metal, drawing a flurry of curses out of him. 

He’s holding the back of his head when he shoots Sam a glare. “Fuck me, what the hell?”

Sam grins sharp at Dean standing there acting like he has no idea why his little brother might be up here looking for him. “Just give me the book, Dean.”

Dean looks at him like he thinks Sam’s the one who just hit his head. “I don’t have your copy of ‘Fifty Shades’,” he snaps. “Wouldn’t be touching that thing without gloves on.”

Sam stares at him. By now, he’d know. Dean might keep a straight face but his eyes give him away, that tiny spark of mischief they hold. 

He doesn’t have it. 

“Okay. Sorry.”

He leaves Dean to go back to the car, muttering under his breath, and goes back downstairs. But if Dean doesn’t have it, who does?

++

They share a hunt two states over and a long, tired drive home before Sam finds out. He should have known, really; if it wasn’t him, and it wasn’t Dean, it only left one other person. 

It’s only when he goes back to his room, towel around his waist after a shower, that he knows for sure. 

The book is lying on his pillow. Coloured post-it notes stick out from among the pages. Sam pounces on it, excited without knowing why. He flicks through the pages, recognising the handwriting, and quickly scanning the notes. 

Cas has been busy editing the book. Every section is marked with corrections or suggestions, some with question marks and a couple with thick black crosses. 

One of them for some creepy fucking reason involves hooding the angel and Sam’s sure that’s one chapter they’d have skipped anyway. 

He strokes his finger across Cas’s handwriting, wondering when he did this. If there’s something that he wants to try before anything else. 

And beyond grateful that he, Sam, won’t blunder into another mistake like the last one and hurt the angel he’d die for. 

He hears soft footsteps behind him and turns to see Cas coming in and closing the door. 

He takes off his coat, then the suit jacket, laying them neatly aside. Shows no sign of stopping. 

“I used colour as a preference,” Cas explains. “I thought we could try the yellow ones first.”

There are a lot of yellow post-its in the book. 

“Which one?” Sam asks. 

Cas smiles at him. “Surprise me.”

 

 


End file.
